Can anyone throw light on this as to where i have gone wrong?

I would say your biggest mistake is that you've chosen SWIG, but I'm biased :)

• SWIG or Inline::CPP
• XS or SWIG
• Inline::C vs. XS vs. SWIG

On the other hand, if you want to stick with SWIG, you would greatly help yourself (and anyone trying to help you) by providing an actual error message and actual C++ sourcecode (what swig generates, and Father/son/Grand_Father).